A company which produces a product that requires a constant supply of relatively clean water is planning to expand by adding new process units online. The plant currently uses well water as a supply to its production. The water production from the well is limited. They need to install a system to produce reuse water to reduce the amount of water required from the onsite well in order to increase the production of the plant. Additionally, sewer surcharge costs have been increasing due to the current loading to the local POTW.
The wastewater contains BOD, Nitrogen, and Phosphorus that must be removed for the reuse application. Additionally, the use of chemical coagulants such as alum or PAC is not acceptable because of possible impact on the production process. The process includes and in-loop RBC with an automatic backwashing screen that removes some BOD and nitrifies most of the ammonia from the process.
The reuse system needed to take the backwash from the screen which contains the bulk of the contaminants and treat it to reuse quality standards in a compact footprint. Because the production process produces varying loads of wastewater, the treatment requirements are unique, and the owners of the facility wanted to prove out the reuse system before investing in a large scale wastewater treatment plant, a pilot system was required in order to collect design information and demonstrate the ability of the technology to produce reuse quality water that will reduce the amount of water required from the current wells.
The membrane bioreactor technology was selected because this technology consistently offers the highest water quality. Since footprint and equipment access was also a major consideration, the Dynatec Hybrid MBR system was selected. Because of the external membrane design, all equipment can be accessed and maintained without requiring a process basin for membranes, which also eliminates the requirement of an operator to enter a membrane basin for maintenance.
The pilot unit was installed at the customer’s facility by Dynatec and includes a complete system including screening, biological treatment integrated with a membrane filtration process. The pilot plant has been in operation for more than two years with successful operation. Several different biological treatment processes have been investigated and the full scale system will be designed based on information gathered from piloting.
Biological phosphorus removal has been implemented in a unique process and is successfully removing phosphorus from the system without the use of chemical coagulants.
Due to high concentrations of mixed liquor and long SRT, sludge wasting is minimized. Wasting is carried out to the city sewer for the pilot.
Membrane Bioreactor Pilot